Mouikkai Shite Minai? - Shotaiken Aite No Aitsu To Shika Kimochiyoku Narenai Setsu summary:

It was supposed to be a heartless encounter, bound to end, but they both seemed eager to embrace each other. Chiho, an office lady, has a problem... that problem? Her first time with a man too good, no other man has been able to satisfy her the same way. Going through boyfriends due to this has made her parents worry, as she was going to do something about it... There he was her "first time" Soma, the man who started this all! "I also couldn't forget about you!"